Various systems and components operate in an environment where they are subject to vibrations from surrounding objects. Such systems and components typically exhibit improved performance and/or accuracy when the vibrations are reduced or removed. Some exemplary systems include satellite payloads, which can be subjected to both large-amplitude vibrations during the launch to orbit around the Earth, as well as small-amplitude vibrations at a different frequencies than the large amplitude vibration while operating in orbit. Such payloads can be sensitive to vibrations. They can therefore benefit from appropriate vibration isolation. Particularly, damping elements are included in the vibration isolation. One example of a passive damping and isolation system is the D-STRUT® isolation strut, manufactured by Honeywell, Inc. of Morristown, N.J. The D-STRUT® isolation strut is a three-parameter vibration isolation system that mechanically acts like a spring (KA) in parallel with a series spring (KB) and damper (CA) and is disclosed in U.S. Pat. No. 5,332,070 entitled “Three Parameter Viscous Damper and Isolator” by Davis et al. and U.S. Pat. No. 7,182,188 entitled “Isolator Using Externally Pressurized Sealing Bellows” by Ruebsamen et al. These patents are hereby incorporated by reference.
Isolation systems are typically tuned for a specific vibration amplitude and resonant frequency. As previously described, some systems can experience different vibration amplitudes at different frequencies. It can be difficult for a single passive isolation system to isolate both types of vibration. Accordingly, vibration isolation systems, such as those for space satellite payloads, are typically tuned to a desired resonant frequency to optimally isolate one vibratory amplitude and frequency at the expense of effectiveness in isolating the other. Isolation systems are often designed or tuned to isolate small-amplitude on-orbit vibrations. Consequently, a satellite payload will frequently experience unmitigated large-amplitude vibrations during launch to orbit. As a result, the satellite payload is often reinforced with certain features and/or structures to survive large amplitude vibrations. The reinforcing features require additional volume in the payload area and impose additional energy costs during launch. Additionally, while useful during launch, once in orbit the reinforcing features or structures typically have no utility.
It would be beneficial to design a single passive vibration isolator which can be tuned to reduce both small- and large-amplitude vibrations during launch and orbit of a satellite payload. Other systems besides satellite systems may similarly benefit from such vibration isolation.